JP2008199703A - Low-voltage power distribution system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the voltage of a connection point with a low-voltage power distribution line of a power user at an end of a low-voltage power distribution line from exceeding a predetermined value by suppressing voltage rise due to reverse power flow by employing a simple means of adding an inexpensive small device. <P>SOLUTION: The low-voltage power distribution system has a structure in which a plurality of transformers 12, 22 are connected to a high-voltage power distribution line 10 extending from a system power source, low-voltage power distribution lines 13, 23 are connected to the transformers 12, 22 and a large number of power users A-E, X-Z having a solar power generators 14a-14e, 24a-24c for causing a reverse power flow to the system power source are connected like branches to each of the low-voltage power distribution lines 13, 23. In this system, a changeover switch 30 for switching from a connection point 15e to a terminal point 25d is provided between the connection point 15e between a low-voltage power distribution line 13 of a power user E which has a voltage increase due to the reverse flow of the solar power generators 14a-14e exceeds the predetermined value, and the terminal point 25d of another low-voltage distribution line 23 adjacent to the low-voltage power distribution line 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a low-voltage distribution system in which a plurality of transformers are connected to a high-voltage distribution line extending from a system power supply and a low-voltage distribution line is connected to each transformer, and a reverse power flow is generated with respect to the system power supply. The present invention relates to a low-voltage distribution system in which a large number of power consumers having a distributed power source such as a solar power generation device are connected to each low-voltage distribution line in a branch shape.

  FIG. 6 shows a low-voltage distribution system in which one low-voltage distribution line 3 is connected to a high-voltage distribution line 1 extending from a system power supply (not shown) via a transformer 2 (post transformer).

  As shown in the figure, in this low-voltage distribution system, a large number of power consumers A to E having photovoltaic power generation devices 4a to 4e as distributed power sources that generate a reverse power flow with respect to the system power supply are connected to the low-voltage distribution line 3 It is configured to be connected in a branch shape. Each electric power consumer A to E is supplied with electric power through the service lines 6a to 6e from connection points 5a to 5e (electric poles installed for each electric power consumer A to E) with the low-voltage distribution line 3, and each electric power consumer From A to E, reverse power flow (see arrows in the figure) is generated in the low-voltage distribution line 3 by the generated power of the solar power generation devices 4a to 4e.

Due to the occurrence of the reverse power flow, the voltage V at the connection points 5a to 5e with the low voltage distribution lines 3 of the electric power consumers A to E has characteristics as shown in FIG. That is, the voltage _VA at the connection point 5a with the low voltage distribution line 3 of the power consumer A located in the immediate vicinity of the transformer 2 is set to the minimum value, and the other power consumers B to The voltage at the connection points 5b to 5e with the low-voltage distribution line 3 of E gradually increases, and the connection point 5e with the low-voltage distribution line 3 of the power consumer E located at the end of the low-voltage distribution line 3 (hereinafter referred to as the end point) The voltage V _{E at the same time} may exceed the specified value V ₀ .

Here, when the photovoltaic power generators 4a to 4e in the respective power consumers A to E cause the generated power to flow backward to the low voltage distribution line 3, the voltage V _A at the connection points 5a to 5e with the low voltage distribution line 3 is obtained. -V _E (actually the terminal voltage of the photovoltaic power generators 4a-4e) outputs a reactive power so that it does not exceed the specified value V ₀ , and further has a function of suppressing the voltage rise by controlling the active power. is doing.

However, when the outputs of the above-described solar power generation devices 4a to 4e are large or high in density, even if the solar power generation devices 4a to 4e output reactive power, they are connected to the low voltage distribution line 3. In some cases, the voltages V _{A to} V _E at 5a to 5e cannot be maintained within the specified value V ₀ . In that case, it is conceivable that the output of the active power of the solar power generation devices 4a to 4e is suppressed to avoid a voltage rise, but the solar power generation devices 4a to 4e have a limited time zone in which high output can be obtained. Suppressing the output of active power during this time period is not preferable because the opportunity to use natural energy is impaired.

As a means for solving this problem, for example, as shown in FIG. 8, there is a method of inserting a reactor 7 in series on the secondary side of the transformer 2 only when it is necessary to generate a voltage rise (for example, non-patent document). 1). By inserting this series reactor 7, as shown in FIG. 9, the voltages V _{A to} V _E at the connection points 5 a to 5 e with the low-voltage distribution lines 3 in the electric power consumers A to _E are respectively changed to the electric power consumers A to _E. The voltage V _E at the connection point 5e with the low voltage distribution line 3 of the electric power consumer E located at the end of the low voltage distribution line 3 is prevented from exceeding the specified value V ₀ by lowering all at once.
National Institute of Electrical Engineers of Japan No. 2003 6-184 6th volume p319-320 "Voltage fluctuation control method with distributed power system interconnection"

By the way, in the conventional low-voltage distribution system, as described above, the voltage V _E at the connection point 5e with the low-voltage distribution line 3 of the power consumer E located at the end of the low-voltage distribution line 3 does not exceed the specified value V _0. Therefore, the series reactor 7 is inserted into the secondary side of the transformer 2 only when the voltage rise is necessary, and the insertion of the series reactor 7 allows the low-voltage distribution lines 3 in the electric power consumers A to E to The voltages V _{A to} V _E at the connection points 5a to 5e are lowered at the power consumers A to E at once (see FIGS. 8 and 9).

  However, when it is set as the structure which inserts the serial reactor 7 in the secondary side of the transformer 2 as mentioned above, the apparatus containing the serial reactor 7 must be installed, and a large current flows into the serial reactor 7 It becomes a large capacity equipment. As a result, there is a problem that the equipment cost increases and the equipment becomes large.

  Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to suppress a voltage increase due to reverse power flow by a simple means for adding a low-priced and small-sized device, and a low-voltage distribution line. An object of the present invention is to provide a low voltage distribution system that can prevent a voltage at a connection point with a low voltage distribution line of a power consumer located at the end of the power line from exceeding a specified value.

  As a technical means for achieving the above-described object, the present invention is configured such that a plurality of transformers are connected to a high-voltage distribution line extending from a system power supply, and a low-voltage distribution line is connected to each transformer. In a low-voltage distribution system in which a large number of power consumers with distributed power sources that generate reverse power flow are connected to each low-voltage distribution line in a branch shape, the power demand due to the reverse power flow of the distributed power source exceeds a specified value A switching switch that switches the contact point from the connection point to the end point is provided between the connection point of the house low-voltage distribution line and the terminal point of another low-voltage distribution line adjacent to the low-voltage distribution line. To do.

  Here, the voltage increase due to the reverse flow of the distributed power source is predetermined at the terminal point of the low voltage distribution line adjacent to the low voltage distribution line of the electric power consumer where the voltage increase due to the reverse flow of the distributed power source exceeds a predetermined specified value. The condition is that the specified value is not exceeded.

  Under this condition, the connection point between the low-voltage distribution line of the electric power consumer whose voltage rise due to reverse power flow of the distributed power source exceeds a specified value and another low-voltage distribution line adjacent to the low-voltage distribution line. The contact point is switched from the connection point to the end point by a switching switch inserted between the end point of the electric wire.

  As a result, a power consumer whose voltage rise due to reverse power flow of a distributed power source exceeds a predetermined specified value will be connected to the terminal point of another low-voltage distribution line, and the power before switching the contact of the switching switch The voltage at the connection point of the low-voltage distribution line, to which the customer's distributed power supply is connected, drops to a predetermined specified value or less. Note that the voltage at the end point of another low-voltage distribution line to which the power consumer's distributed power source is newly connected after switching the contact point of the switching switch rises, but the connection point and end point before switching the contact point of the switching switch If the voltage difference between the points is greater than or equal to a certain value, it can be less than or equal to a predetermined specified value.

  Among a large number of power consumers with distributed power sources that generate reverse power flow to the system power source, power customers whose voltage increase due to the reverse power flow of the distributed power source exceeds a specified value are at the end of the low-voltage distribution line. Not necessarily located. However, the voltage rise due to the reverse power flow of the distributed power source is caused by the cumulative amount of resistance between the power consumers of the low-voltage distribution line toward the end of the low-voltage distribution line. In many cases, the voltage exceeds the predetermined specified value.

  In this case, between the terminal point of the low voltage distribution line of the electric power consumer whose voltage rise due to reverse power flow of the distributed power source exceeds a predetermined specified value and the terminal point of another low voltage distribution line adjacent to the low voltage distribution line Therefore, the contact of the switching switch is switched from the former end point to the latter end point.

  The switching switch according to the present invention has a connection point with a low voltage distribution line of a power consumer whose voltage increase due to reverse power flow of the distributed power source exceeds a predetermined specified value, and a terminal of another low voltage distribution line adjacent to the low voltage distribution line. Measure both voltages at the point, and immediately before the voltage increase due to reverse power flow exceeds the specified value, and when the difference between the voltage at the connection point and the terminal point exceeds a certain value, A configuration in which the contact can be switched to the end point is desirable.

  In this way, from the connection point with the low voltage distribution line of the electric power consumer whose voltage increase due to the reverse power flow of the distributed power source exceeds a predetermined specified value, the terminal point of another low voltage distribution line adjacent to the low voltage distribution line Even when the contact point is switched, both voltages at the connection point and the terminal point can be easily regulated within the range of the predetermined specified value.

  The switching switch according to the present invention preferably has a configuration in which the contact can be switched from the connection point to the end point after a voltage increase due to the reverse power flow continues for a certain period of time.

  In this way, it is possible to eliminate the case where a voltage increase due to reverse power flow occurs instantaneously due to reverse power flow or any other cause, and it is possible to prevent malfunction of the switching switch. Become.

  Further, the switching switch according to the present invention preferably has a configuration in which the switching time of the contact point from the connection point to the terminal point is within the isolated operation detection time of the distributed power source.

  If the switching time in the switching switch is longer than the isolated operation detection time of the distributed power supply, the distributed power supply is detected by the independent operation detection of the distributed power supply before the contact switch from the connection point to the end point is completed by the switching switch. Will stop. Therefore, if the switching time of the contact point from the connection point to the terminal point is within the detection time of the single operation of the distributed power supply, the connection point can be connected by the switching switch without stopping the distributed power supply by detecting the single operation of the distributed power supply. The contact can be reliably switched from the end point to the end point.

  According to the present invention, a connection point between a low-voltage distribution line of a power consumer whose voltage increase due to reverse power flow of the distributed power source exceeds a predetermined specified value, and an end point of another low-voltage distribution line adjacent to the low-voltage distribution line By providing a switching switch for switching the contact point from the connection point to the terminal point, the power consumer whose voltage increase due to the reverse power flow of the distributed power source exceeds a predetermined specified value by the switching switch, It will be connected to the terminal point of another low-voltage distribution line, and the voltage at the connection point of the low-voltage distribution line of the power consumer can be lowered to a predetermined specified value or less.

  As a result, a simple means of adding an inexpensive and small device, that is, a switching switch, prevents the voltage at the end of the low-voltage distribution line from exceeding the specified value, and also increases the voltage due to reverse power flow. Therefore, it is possible to avoid the suppression of the effective power of the distributed power source, so that it is possible to effectively use natural energy such as photovoltaic power generation.

  FIG. 1 is an embodiment of the present invention and shows a schematic configuration of a low-voltage distribution system.

  In the low-voltage distribution system in this embodiment, as shown in the figure, a plurality of transformers 12 and 22 are connected to a high-voltage distribution line 10 extending from a system power supply (not shown) and each transformer 12 and 22 is connected. Low voltage distribution lines 13 and 23 are connected. The above-described transformers 12 and 22 are pole transformers generally installed on a utility pole or the like.

  In this embodiment, two transformers 12 and 22 and two low-voltage distribution lines 13 and 23 connected to the high-voltage distribution line 10 through the transformers 12 and 22 are illustrated, but three or more. The present invention can be similarly applied to the above transformer and three or more low-voltage distribution lines connected to the high-voltage distribution line 10 through the transformer.

  A large number of electric power consumers (for example, ordinary households and factories) are connected to each of the low-voltage distribution lines 13 and 23. In the illustrated embodiment, five power consumers A to E are connected to one low-voltage distribution line 13 in a branch shape, and three power consumers X to Z are connected to the other low-voltage distribution line 23 in a branch shape. The configuration is illustrated.

  In addition, each electric power consumer A-E in one low voltage distribution line 13 is the lead-in wires 16a-16e from the connection points 15a-15e (electric pole installed for every electric power consumer A-E) with the low voltage distribution line 13. The solar power generation devices 14 a to 14 e as distributed power sources that are supplied with power and generate a reverse power flow with respect to the system power source are provided, and the solar power generation devices 14 a to 14 e are connected via the low-voltage distribution line 13 and the high-voltage distribution line 10. Connected to the grid power supply. From each electric power consumer A-E, the reverse power flow (refer arrow in the figure) is generated in the low-voltage distribution line 13 by the generated power of the solar power generation devices 14a-14e.

  Moreover, each electric power consumer XZ in the other low voltage distribution line 23 is the service lines 26a-26c from the connection points 25a-25c (electric pole installed for every electric power consumer XZ) with the low voltage distribution line 23. The solar power generation devices 24 a to 24 c are provided as distributed power sources that are supplied with power and generate a reverse power flow with respect to the system power source, and the solar power generation devices 24 a to 24 c are connected via the low-voltage distribution line 23 and the high-voltage distribution line 10. Connected to the grid power supply. From each electric power consumer XZ, the reverse power flow (refer the arrow in a figure) is generated in the low voltage distribution line 23 with the electric power generated by the solar power generation devices 24a-24c.

When the solar power generation devices 14a to 14e and 24a to 24c installed in the power consumers A to E and X to Z are present in the low voltage distribution systems 13 and 23, the reverse power flow with respect to the system power supply is reduced to the low voltage distribution lines 13, 23 occurs. Due to the occurrence of this reverse power flow, the voltages V _{A to} V _E and V _{X at} the connection points 15a to 15e and 25a to 25c (electric poles) with the low voltage distribution lines 13 and 23 of the electric power consumers _{A to E} and _{X to Z are obtained.} ~V _Z represents a characteristic as shown in FIG. That is, of the connection points 15a to 15e and 25a to 25c with the low-voltage distribution lines 13 and 23 of the power consumers A to E and X to Z, the nearest connection points 15a and 25a connected to the transformers 12 and 22 are connected. The voltage V _A , V _X is the lowest, and the voltage rises from the nearest connection points 15a, 25a toward the ends of the low-voltage distribution lines 13, 23.

As the voltage increases due to the reverse power flow of the solar power generation devices 14a to 14e and 24a to 24c, the resistance between the power consumers of the low-voltage distribution lines 13 and 23 is accumulated toward the ends of the low-voltage distribution lines 13 and 23. Therefore, the voltages at the connection points 15b to 15e and 25b to 25c are sequentially applied from the most recent connection points 15a and 25a connected to the transformers 12 and 22 to both sides (the left and right sides of the connection points 15a and 25a illustrated). It tends to be higher. As a result, as in the case of one low-voltage distribution line 13, the low-voltage distribution lines 13 of a large number of power consumers C to E between the nearest connection point 15 a connected to the transformer 12 and the end of the low-voltage distribution line 13 When the connection point 15c~15e present, defined value V ₀ is the voltage V _E of the predetermined connection point 15e of the low-voltage distribution line 13 of the electric power consumer E located at the end of the low-voltage distribution line 13 as shown in FIG. May be exceeded.

Therefore, one of the power demand located at the end of the low-voltage distribution line 13 home E, i.e., low-voltage distribution lines of electric power consumers E voltage rise due to the reverse flow of the photovoltaic device 14a~14e exceeds a predetermined specified value V ₀ A switching switch 30 for switching the contact point from the connection point 15e to the terminal point 25d is provided between the connection point 15e to the terminal 13 and the terminal point 25d of another low-voltage distribution line 23 adjacent to the low-voltage distribution line 13.

  In the switching switch 30, a connection point 15e to the low voltage distribution line 13 of the electric power consumer E located at the end of the low voltage distribution line 13 is connected to one primary side terminal, and the low voltage is connected to the other primary side terminal. The terminal point 25d of another low-voltage distribution line 23 adjacent to the distribution line 13 is connected, and the solar power generation device 14e of the electric power consumer E located at the end of the low-voltage distribution line 13 is connected to the secondary side terminal. The switching switch 30 is installed in a utility pole to which a power consumer E located at the end of the low-voltage distribution line 13 is connected by a lead-in line 16e.

Here, at the terminal point 25d of another low-voltage distribution line 23 adjacent to the low-voltage distribution line 13 of the power consumer E in which the voltage increase due to the reverse power flow of the solar power generation devices 14a to 14e exceeds a predetermined specified value V ₀ , the voltage rise due to the reverse flow of the photovoltaic device 24a~24c does not exceed the predetermined specified value V ₀ is a condition. That is, the difference between the voltage V _E at the connection point 15e of the power consumer E with the low voltage distribution line 13 of one low voltage distribution line 13 and the voltage V _P at the end point 25d of the other low voltage distribution line 23 is constant. It needs to be greater than or equal to the value.

Difference in this way, the voltage V _E at the connection point 15e to the low-voltage distribution line 13 of the electric power consumers E in one of the low-voltage distribution line 13, the voltage V _P at the end point 25d of the other low-voltage distribution line 23 Is smaller than a certain value, there is a possibility that the voltage V _P at the terminal point 25d of the other low-voltage distribution line 23 will rise and exceed the predetermined specified value V ₀ by switching the contact by the switching switch 30 as will be described later. Because there is.

Under a state satisfying the above conditions, and the connection point 15e of the voltage rise due to the reverse flow of the photovoltaic device 14a~14e is a low-voltage distribution line 13 of the electric power consumer E exceeding a predetermined specified value V _0, the A switching switch 30 inserted between the low-voltage distribution line 13 and a terminal point 25d of another adjacent low-voltage distribution line 23 switches the contact point from the connection point 15e to the terminal point 25d as shown in FIG.

By switching the contact of the switching switch 30, the electric power consumer E whose voltage increase due to the reverse power flow of the photovoltaic power generation devices 14 a to 14 e exceeds the predetermined specified value V ₀ is disconnected from the one low-voltage distribution line 13 and the low voltage It is connected to the end point 25 d of another low-voltage distribution line 23 adjacent to the distribution line 13. At this time, the connection point 15e of one low-voltage distribution line 13 becomes a terminal point, and the terminal point 25d of the other low-voltage distribution line 23 becomes a connection point.

As a result, in one low-voltage distribution line 13, the photovoltaic power generation device 14 e of the power consumer E at the end position that has generated the reverse power flow disappears. Therefore, as shown in FIG. The voltage V _E at the connection point 15e of the electric wire 13 drops and becomes a predetermined specified value V ₀ or less. The voltage V _P at the end point 25d of another low-voltage distribution line 23 which photovoltaic device 14e of the electric power consumers E after contact switching of the switching switch 30 is newly connected is increased, but the switching switch 30 Since the voltage difference between the connection point 15e of one low-voltage distribution line 13 and the terminal point 25d of the other low-voltage distribution line 23 before the contact switching is equal to or greater than a certain value, the voltage V _P at the terminal point 25d is The predetermined specified value V ₀ is not exceeded.

However, after switching the contact of the switching switch 30, the voltage V _E at the terminal point 15e of one low-voltage distribution line 13 becomes lower than a predetermined specified value V _{0 and} the connection of the other low-voltage distribution line 23 is reversed. When the difference between the voltage V _P at the point 25d and the voltage V _E at the terminal point 15e of one low-voltage distribution line 13 becomes larger than a certain value, the other low-voltage distribution line 23 is switched by the switching switch 30. The contact point is switched from the terminal point 25d to the connection point 15e of one of the low-voltage distribution lines 13 and returned.

Thus the result, only installing a small switch switch 30 is inexpensive, predetermined voltage V _E at the connection point 15e to the low-voltage distribution line 13 of the electric power consumer E located at the end of the low-voltage distribution line 13 the specified value can not exceed V _0, also it can be avoided to suppress the active power of the photovoltaic device 14a~14e with voltage rise due to the reverse power flow, the natural energy such as solar power Effective utilization can be achieved.

In this embodiment, the voltage increase due to the reverse power flow of the solar power generation devices 14 a to 14 e is caused by the cumulative resistance between the power consumers of the low-voltage distribution line 13 being sequentially accumulated toward the end of the low-voltage distribution line 13. Since it occurs, the case where the voltage V _E at the connection point 15e with the low voltage distribution line 13 of the electric power consumer E located at the end of the low voltage distribution line 13 exceeds the predetermined specified value V ₀ is described.

However, among many electric power consumers having solar power generation devices, there are also electric power consumers having solar power generation devices that do not generate a reverse power flow with respect to the system power supply. For this reason, the voltage at the connection point of the power consumer located on the way to the end of the low-voltage distribution line with the low-voltage distribution line may exceed a predetermined specified value V ₀ .

In this case, when the voltage at the connection point of the low voltage distribution line of the power consumer located halfway up to the end of the low voltage distribution line 13 exceeds a predetermined specified value V ₀ , the low voltage distribution line of the power consumer and The switching switch is switched from the former connection point to the latter end point between this connection point and the end point of another low-voltage distribution line adjacent to the low-voltage distribution line.

The switching switch 30 in this embodiment is controlled to open and close by a control device 38 including a voltage comparison unit 32, a timer unit 34, and a determination unit 36 as shown in FIG. First, in the voltage comparison unit 32, the electric power consumer E in which the voltage increase due to the reverse power flow of the photovoltaic power generation devices 14 a to 14 e exceeds a predetermined specified value V ₀ , that is, the electric power consumer E located at the end of the low-voltage distribution line 13. Both voltages V _E and V _P at the connection point 15e to the low-voltage distribution line 13 and the terminal point 25d of another low-voltage distribution line 23 adjacent to the low-voltage distribution line 13 are measured by the instrument transformer PT.

  On the other hand, in the timer part 34, it is monitored whether the voltage rise by the reverse power flow of the solar power generation devices 14a-14e continues for a predetermined time. By monitoring whether or not the voltage increase continues for a predetermined time by the timer unit 34, it is possible to eliminate a case where the voltage increase instantaneously occurs due to reverse power flow or any other cause. It is possible to prevent malfunction of the switch 30 in advance.

In this way, based on the output from the voltage comparison unit 32, immediately before the voltage increase due to the reverse power flow exceeds the predetermined specified value V ₀ , and the difference in voltage between the connection point 15e and the end point 25d (V _E − V _P ) is determined to be equal to or greater than a certain value, and further, based on the output from the timer unit 34, when the voltage increase due to the reverse power flow of the solar power generation devices 14a to 14e continues for a predetermined time, Based on the output from the determination unit 26, the switching switch 30 switches the contact point from the connection point 15 e of the low-voltage distribution line 13 to the end point 25 d of the low-voltage distribution line 23. By this contact switching, the power consumer E is disconnected from one low-voltage distribution line 13 and connected to the other low-voltage distribution line 23.

  In addition, in the low voltage power distribution system in which the photovoltaic power generation devices 14a to 14e and 24a to 24c possessed by electric power consumers are connected to the system power source, when the power failure occurs in the system power source, In order to prevent isolated operation, the solar power generation devices 14a to 14e and 24a to 24c are stopped after the isolated operation detection time.

  Therefore, when the switching time in the switching switch 30 is longer than the isolated operation detection time of the photovoltaic power generation device 14e, the photovoltaic power generation device is completed before the switching switch 30 completes switching of the connection point 15e to the terminal point 25d. The solar power generation device 14e is stopped by detecting the single operation 14e.

  Therefore, in the switching switch 30, the switching of the contact point from the connection point 15e to the end point 25d is reliably completed by the switching switch 30 without stopping the photovoltaic power generation apparatus 14e by detecting the isolated operation of the photovoltaic power generation apparatus 14e. In order to be able to do so, it is necessary that the switching time of the contact point from the connection point 15e to the end point 25d is within the isolated operation detection time of the solar power generation device 14e.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the scope of the present invention. The scope of the present invention is not limited to patents. It includes the equivalent meanings recited in the claims, and the equivalent meanings recited in the claims, and all modifications within the scope.

In embodiment of this invention, it is a schematic block diagram which shows the state before switching by a switching switch in a low voltage | pressure distribution system. It is a characteristic view which shows the voltage in the connection point with the low voltage distribution line of each electric power consumer in the low voltage distribution system of FIG. In embodiment of this invention, it is a schematic block diagram which shows the state after switching by the switching switch in a low voltage | pressure distribution system. It is a characteristic view which shows the voltage in the connection point with the low voltage distribution line of each electric power consumer in the low voltage distribution system of FIG. It is a control block diagram which shows the switching switch used with the low voltage | pressure distribution system of FIG. It is a schematic block diagram which shows the prior art example of a low voltage | pressure distribution system. It is a characteristic view which shows the voltage in the connection point with the low voltage distribution line of each electric power consumer in the low voltage distribution system of FIG. It is a schematic block diagram which shows the other conventional example of a low voltage | pressure distribution system. It is a characteristic view which shows the voltage in the connection point with the low voltage distribution line of each electric power consumer in the low voltage distribution system of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 High voltage distribution line 12 Transformer 13 Low voltage distribution line 14a-14e Distributed type power supply (solar power generation device)
15a-15e Connection point 22 Transformer 23 Low voltage distribution line 24a-24c Distributed type power supply (solar power generation device)
25a to 25e Connection point 25d Terminal point 30 Switching switch A to E Electric power consumer X to Z Electric power consumer

Claims (5)

  A number of transformers are connected to the high-voltage distribution line extending from the system power supply, and a low-voltage distribution line is connected to each transformer. In the low-voltage distribution system connected to each of the low-voltage distribution lines in a branch shape, a connection point with a low-voltage distribution line of a power consumer whose voltage increase due to reverse power flow of the distributed power source exceeds a predetermined specified value, and the low-voltage distribution line A switching switch for switching a contact point from the connection point to the terminal point is provided between the terminal point of the other low-voltage distribution line adjacent to the terminal.   The low-voltage distribution system according to claim 1, wherein a connection point with a low-voltage distribution line of a power consumer whose voltage rise due to reverse power flow of the distributed power source exceeds a predetermined specified value is an end point of the low-voltage distribution line.   The switching switch is a connection point with a low voltage distribution line of a power consumer whose voltage rise due to reverse power flow of a distributed power source exceeds a predetermined specified value, and a terminal point of another low voltage distribution line adjacent to the low voltage distribution line. Each of the two voltages, and immediately before the voltage increase due to the reverse power flow exceeds a predetermined specified value, and when the voltage difference between the connection point and the terminal point becomes a certain value or more, from the connection point. The low-voltage power distribution system according to claim 1 or 2, wherein the contact point can be switched to an end point.   The low-voltage distribution system according to any one of claims 1 to 3, wherein the switching switch is capable of switching a contact from a connection point to a terminal point after a voltage increase due to reverse power flow continues for a certain time.   The low-voltage distribution system according to any one of claims 1 to 4, wherein the switching switch has a switching time of a contact point from a connection point to a terminal point within an isolated operation detection time of a distributed power source.

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